In the Google developers recommendation for optimizing JavaScript code, they mention that the best way to declare/initialize new variables for object is to use the prototype. For instance, instead of: Use: However, in my case I have a dependency between variables, for instance: Using this.toWhom outside of th…
Tag: variables
is there a way to exchange variables between JavaScript and PHP
I have build a website in Drupal, and I am trying to create a fun way to get members involved with the site by building a userpoint system, the system is all in place, but I’m trying to make a shop where they can buy ‘titles’. This is the script I wrote for the shop, with a bit of error
Pass variables by reference in JavaScript
How do I pass variables by reference in JavaScript? I have three variables that I want to perform several operations to, so I want to put them in a for loop and perform the operations to each one. Pseudocode: What is the best way to do this? Answer There is no “pass by reference” available in Java…
Define a global variable in a JavaScript function
Is it possible to define a global variable in a JavaScript function? I want use the trailimage variable (declared in the makeObj function) in other functions. Answer As the others have said, you can use var at global scope (outside of all functions and modules) to declare a global variable: (Note that that…
Increase and decrease a variable until a number is reached in Javascript
How can I increase and decrease a variable in Javascript until 100 and when 100 is reached it should start decreasing. So accuracyBarValue should start in 0, increase to 100, and when 100 is reached it should go to 0, and then repeat procedure. This in intervals of 10. I use this in a very simple JS game, whe…
How to run a function in JavaScript every time a variable changes?
Is there a way in JavaScript to have something like an event that listens to changes in a variable? so when its value is modified the event triggers and then I can call a function. To put this more into context I have a function which handles the html rendering of an array of objects, and I want that function
JavaScript: Split array into individual variables
Considering this data structure: Looping through each vehicles item, is there a way to reassign the array elements to individual variables all in one shot, something like: … I’m trying to get away from doing: Just curious since this type of thing is available in other programming languages. Thanks…
Get all Javascript Variables?
Is there a way for javascript to detect all assigned variables? For example, if one js file creates a bunch of vars (globally scoped), can a subsequent file get all the vars without knowing what they’re named and which might exist? Thanks in advance 🙂 EDIT, Question Part 2: How do I get the values of th…
How can I determine if a variable is ‘undefined’ or ‘null’?
How do I determine if variable is undefined or null? My code is as follows: But if I do this, the JavaScript interpreter halts execution. Answer You can use the qualities of the abstract equality operator to do this: Because null == undefined is true, the above code will catch both null and undefined.
Declaring multiple variables in JavaScript
In JavaScript, it is possible to declare multiple variables like this: …or like this: Is one method better/faster than the other? Answer The first way is easier to maintain. Each declaration is a single statement on a single line, so you can easily add, remove, and reorder the declarations. With the sec…